# GROUP BY
Groups data by specified columns and optionally applies aggregate functions.
## Syntax
```basic
result = GROUP BY data, column
result = GROUP BY data, column, aggregates
```
## Parameters
| Parameter | Type | Description |
|-----------|------|-------------|
| `data` | Array | The data array to group |
| `column` | String | Column name to group by |
| `aggregates` | Object | Optional aggregate functions to apply |
## Description
`GROUP BY` organizes rows of data into groups based on matching values in a specified column. When combined with aggregate functions, it calculates summary values for each group.
## Examples
### Basic Grouping
```basic
orders = FIND "orders", "status=completed"
grouped = GROUP BY orders, "category"
FOR EACH group IN grouped
TALK "Category: " + group.key + " - Count: " + group.count
NEXT
```
### With Aggregates
```basic
sales = FIND "sales", "year=2025"
summary = GROUP BY sales, "region", #{
total: "SUM(amount)",
average: "AVG(amount)",
count: "COUNT(*)"
}
FOR EACH region IN summary
TALK region.key + ": $" + region.total + " (" + region.count + " sales)"
NEXT
```
### Multiple Level Grouping
```basic
' First group by category, then by month
products = FIND "orders", "year=2025"
by_category = GROUP BY products, "category"
FOR EACH cat IN by_category
TALK "Category: " + cat.key
by_month = GROUP BY cat.items, "month"
FOR EACH month IN by_month
TALK " " + month.key + ": " + month.count + " orders"
NEXT
NEXT
```
## Return Value
Returns an array of group objects, each containing:
| Property | Description |
|----------|-------------|
| `key` | The grouping value |
| `items` | Array of items in this group |
| `count` | Number of items in group |
| Additional | Any requested aggregates |
## Supported Aggregates
| Function | Description |
|----------|-------------|
| `SUM(column)` | Sum of values |
| `AVG(column)` | Average of values |
| `MIN(column)` | Minimum value |
| `MAX(column)` | Maximum value |
| `COUNT(*)` | Number of rows |
## Sample Conversation
Show me sales by region
14:30
📊 Sales by Region (2025)
North America: $245,000 (127 sales)
Europe: $189,500 (98 sales)
Asia Pacific: $156,200 (84 sales)
Latin America: $67,300 (42 sales)
14:30
## See Also
- [AGGREGATE](./keyword-aggregate.md) - Single aggregate calculations
- [PIVOT](./keyword-pivot.md) - Cross-tabulation of data
- [FILTER](./keyword-filter.md) - Filter data before grouping
- [FIND](./keyword-find.md) - Retrieve data to group
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